We present a method for the preliminary determination of focal mechanisms (PDFM), based on the inversion of deviatoric moment tensor components from depleted datasets of mantle wave spectral amplitudes. The latter are found to be largely insensitive to errors in epicentral estimates, which can hamper the inversion of the full complex spectrum under real-time operational conditions. Robust solutions can be obtained from Rayleigh wave spectra at as few as three stations, and from a combination of Rayleigh and Love waves at only two stations, provided they sample 60°in azimuth. The systematic application of this method to a dataset of 43 large earthquakes during 1996-1999 yielded mechanisms rotated an average of only 17°from the published Harvard CMT, a figure comparing favorably with the case of other catalogues, such as the USGS moment tensor solutions. (C) 2000 Elsevier Science B.V. All rights reserved.
- Love wave
- Preliminary determination of focal mechanisms
- Rayleigh wave
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Physics and Astronomy (miscellaneous)
- Space and Planetary Science